package algorithm.problems.string;

/**
 * Created by gouthamvidyapradhan on 20/01/2018.
 *
 * The count-and-say sequence is the sequence of integers with the first five terms as following:

 1.     1
 2.     11
 3.     21
 4.     1211
 5.     111221
 1 is read off as "one 1" or 11.
 11 is read off as "two 1s" or 21.
 21 is read off as "one 2, then one 1" or 1211.
 Given an integer n, generate the nth term of the count-and-say sequence.

 Note: Each term of the sequence of integers will be represented as a string.

 Example 1:

 Input: 1
 Output: "1"
 Example 2:

 Input: 4
 Output: "1211"

 */
public class CountAndSay {

    /**
     * Main method
     * @param args
     */
    public static void main(String[] args) throws Exception {
        System.out.println(new CountAndSay().countAndSay(4));
    }

    public String countAndSay(int n) {
        String result = "1";
        for(int i = 1; i < n; i ++){
            int count = 1;
            char num = result.charAt(0);
            StringBuilder temp = new StringBuilder();
            for(int j = 1, l = result.length(); j < l; j++){
                if(result.charAt(j) == num){
                    count++;
                } else{
                    temp = temp.append(String.valueOf(count)).append(String.valueOf(num));
                    num = result.charAt(j);
                    count = 1;
                }
            }
            temp = temp.append(String.valueOf(count)).append(String.valueOf(num));
            result = temp.toString();
        }
        return result;
    }
}
